Spark gap and shield



Dec. 10, I929. E. E. BIDWELL SPARK GAP AND SHIELD Filed Feb. 14, 1927INVENTOR. EARL E. BIDWELL Maw A TTORNE Y.

Patented Dec. 10, 1929 EAR-L E. BIDVELL, OF WICHITA, KANSAS SPAR-K GAPAND SHIELD AppIication filed February 14, 1527. Serial 230. 188,143.

This invention relates to engines and the primary object thereof is toprovide a combined intensifier and moistureshedding hood to beassociated with the spark plug so that theintensity of the spark at thepoint of ignition willbe enhanced and whereby the device will act as ashedding means to prevent short circuiting' -between the positiveelectrode and the shell due to the accumula- 'tion of moisture along theinsulating porcelain. In those plugs to the electrodes of which thesaidwire'sare directly attached, there is always danger of shortcircuiting because rain or other moisture may flow along 1.5 theinsulation on to the plug shell to thereby form a short path for thecurrent with practically no resistance. My invention eliminates thepossibility of'this, due to the fact that no water or other moisture can"pass di- 2o rectly from the electrode to the shell, The hoodefficiently sheds the water away from contact with the electrode andsince the gap between the hood and the shell is greater than thegapbetween the hood and the elec- 2 trode, the spark will always jumpacross the intensifier gap'which is the space between the edge of anopening in the hood and the electrode. I have provided means formaintaining a uniform distance between the hood or intensifierelementand the electrode so that the proper intensifying gap can bemaintained. V

Other objects and advantages of the invention will be apparent byreference to the following description in connection with theaccompanying drawings in which:

' Figfl is an elevation of a spark plug showing the-shield in position,parts removed for convenience of illustration.

' Fig. 2 is a top end view of Fig. 1.

Fig. 3 is a sectional View through the shield and insulations connectedtherewith.

The device is illustrated as comprising a metallic hood 1 in the form ofan inverted cup having a central aperture 2 through which the upper endof the positive electrode 3 extends. The aperture has a greatercrosssectional area than that of the electrode so that a spark gap isprovided between the edgeiof the aperture and the electrode. Un-

der the top B of the hood is an insulating disc a of porous lnsulatingmaterial. The diameter of the disc is equal to the inner diameter of thecup-shaped hood and the orifice through which the electrode extends isof substantially the same diameter as that of the electrode so that thehood is rigidly held against the jam nut of the spark plug to therebymaintain a uniform annular spacing between the electrode and the edge ofthe opening 2 so that the spark gap between the edge of the opening 2and the electrode is equally spaced entirely around the electrode. Onthe outer face (that is, on top of the hood) is an insulating disc 5overlapping the edge of the opening 2 and snugly fitting about theelectrode so that when the nut 6 is screwed on to the electrode 3, thehood will be protected against liability of moisture entering the sparkgap to form a short circuit. On the hood is a binding post 7 to whichmay be fastened the said wire 8 in the usual man ner. C is the insulatoror porcelain for the electrode 3 and D is a spark plug shell. It will beobserved that the inner diameter of the hood is considerably greaterthan the outer diameter of the porcelain and that there is aconsiderable space between the bottom edge of the hood and the nut A ofthe spark plug so that danger of the spark umping from the lower edge ofthe hood to the shell of the spark plug will be entirely eliminated.Since the wall of the hood is spaced a considerable distance from theporcelain C and since the disc 5 prevents moisture from passingthroughthe opening 2, it will be apparent'that danger of rain or moisturefilming along the porcelain and thereby forming a short circuit will beeliminated.

In some cases I may desire to dispense with the intensifier feature ofmy invention and still retain the advantages of the moisture shed orprotector, in which event, the disc 4; may be removed from the interiorof the cup and it together with the disc 5 may be held against the upperface B of the cup by the nut 6, then the current will pass directly fromconductor 8, through the binding post '7 to hood 1, through the jam nutof the spark plug to electrode 3 without having an intensifying effect.The device can be read ily applied to any conventional spark plug, so Ihave shown it applied to a common type of plug now generally used.

What I claim and desire to secure by Letters-Patent is: I

1. In a spark gap and shield, in combination with a spark plug, a hoodhaving an aperture in the top thereof to receive the electrode of theplug, said aperture being greater in diameter than the electrode, aninsulation member positioned in the top of the hood, an insulationmember to engage on the outside of the top of the hood, aperturesthrough said insulations in registry with each other and concentricallypositioned to the aperture in the hood to receive the electrode snugly,a binding post attached to the exterior and near the top of the hood,means for connecting the current wire to the post. 7

2. In a spark gap and shield, in combination with a spark plug for aninternal combustion engine, a hood having an aperture concentricallypositioned in the top thereof to engage on the electrode of the plugwith the contact to "form a gap peripherally around the electrode, aninsulation member to fit snugly in the top of the hood, an aperturecentrally positioned in said insulation to snugly engage on theelectrode as centering means therefor in the aperture of the hood, anapertured insulation for the exterior of the hood to engage with theelectrode, and a nut threadedly engaging on the electrode as bindingmeans therefor to the hood, means for connecting the electric current tothe hood in close proximity to the top thereof, all as, and for thepurpose described.

3. In combination with a spark plug having an electrode extendingtherefrom, of a combined spark gap and moisture shedding hood associatedtherewith, the hood having an opening of greater diameter than theelectrode,the edge of the opening surrounding the electrode, aninsulating disc within the hood, the periphery of which bears againstthe outer wall of the hood and through the center of which the electrodeextends so that the edge of the opening of the hood will be uniformlyspaced about the electrode and a binding post on the hood.

4. Incombination with a spark plug having an electrode extendingtherefrom, of a combined spark gap and moisture shedding hood associatedtherewith, the hood having an opening of greater diameter than theelectrode, the edge of the opening surrounding the electrode, aninsulating disc within the hood, the periphery of which bears againstthe outer wall of the hood and through the center of which the electrodeextends so that the edge of the opening of the hood will be uniformlyspaced about the electrode, a washer on the outer face of the hoodoverlapping the edge of the opening and snugly fitting the electrode, anut on the electrode bearing against the second mentioned washer forbinding the hood to the spark plug and a binding post on the hood.

5. In combination with a spark plug having an electrode extendingtherefrom, of a cup-shaped hood associated therewith, said hood having acentral opening in its top of greater diameter than that of theelectrode so that the edge of the opening is spaced from the electrode,a washer within the hood, the edge of which bears against the inner faceof the hood to centralize it with respect to the electrode so that theedge of the opening will be spaced a uniform distance from theelectrode, a washer on the electrode bearing against the outer face ofthe hood overlapping the edge of the opening, a nut on the electrodebinding the washer against the hood and a binding post on the hood.

6. In a spark gap and shield, in combination with a spark plug, a metalhood having an aperture concentrically positioned in the closed endthereof, the aperture being larger in diameter than the electrode of theplug, whereby a spark gap is formed, an insulation fitting snugly on theinside of the closed end of the hood and having an aperture centrallypositioned, the aperture to fit snugly on the electrode as closing meansfor the gap, and a nut threadedly engaging on the electrode as securingmeans for the hood to the outer end of the plug, a binding postintegrally connected near the closed end of the hood.

7. In a spark gap and shield, in combination with a spark plug having anelectrode axially extending theret-hrough, 'a metal hood having anaperture concentrically positioned in the closed end of the hood, theaperture being larger in diameter than the electrode of the plug, theinner end of the hood being spaced longitudinally from the the metalbody of the plug, a binding post integrally connected to the hood inclose proximity to the closed end, an insulation fitting snugly on theinside of the closed end of the hood and having an aperture centrallypositioned and snugly fitting on the electrode as means toconcentrically position the hood to the outer end of the plug, aninsulation positioned on the outside, of the closed hood as concealingmeans for the aperture in the metal hood, and means to bind saidinsulations firmly together and simultaneously the hood to the sparkplug, all as and for the purpose described.

8. A current-intensifying device compris ing a cup-shaped member ofcurrent-conducting mater1a=l and containing an aperture, a disk ofcurrent-lnsula'ting material snugly fitting in said i'nember andcontaining an aperture-in registration with the aperture 1n said member,said'apertures being provided to receive the upper end of the centralelectrode of a spark plug, the aperture in said member being of greaterdiameter than the aperture in said disk.

9. A current-intensifying device comprising a cup-shaped member ofcurrent-conducting material for connection with one terminal of anelectric ignition circuit and the mounting thereof on the centralelectrode of a spark plug, and means engaging said electrode forsecuring said member on said electrode in spaced relation to the latterand insulating said member from said electrode.

10. In combination with a spark plug having an electrode projectingoutwardly therefrom, a spark-gap device comprising an invertedcup-shaped member of currentconducting material for connection with oneof the current-conducting wires and containing an opening therethroughof greater diameter than the diameter of said electrode and throughwhich said electrode extends but out of contact with the wall of saidopening, an insulating disk within said member and containing an openingconcentric with the opening in said member but of smaller diameter thanthe latter and through which said electrode extends.

11. In combination with a spark plug having an electrode projectingoutwardly therefrom, a spark-gap device comprising an invertedcup-shaped member of currentconducting material for connection with oneof the current-conducting wires and containing an opening therethroughof greater diameter than the diameter of said electrode and throughwhich said electrode extends but out of contact with the wall of saidopening, and an insulating disk Within, and closely fitting, said memberand containing an opening concentric with the opening in said member butof smaller diameter than the latter and through Which said electrodeextends.

In testimony whereof I aflix my signature.

EARL E. BI'DWELL.

